This invention relates to a vacuum transfer device for use in connection with the manufacture or testing of electronic integrated circuit chips and the like under vacuum.
The fabrication and testing of present-day electronic circuitry often requires processing under vacuum, for example, because the processing steps per se must be performed under vacuum, or cleanliness requirements can be met only if enough dust-carrying air or gas has been pumped from the environment. The manufacture of integrated circuits typically involves a plurality of steps of different nature, such as etching, evaporation, sputtering, etc., which for various reasons cannot be performed at a single location. In known processing apparatus, when a device being manufactured or tested is removed from one work station and transferred to the next, the first work station must be vented and the second evacuated. Including the required heating of the system, the transfer process could easily take tens of hours to complete. The yield achievable with these systems is reduced because the repeated venting and evacuating adversely affects certain devices.
Prior art transport systems and handling devices are described, for example, in the IBM Technical Disclosure Bulletin, Vol. 18, No. 11, pp. 3669-3676 and 3679-3080 (April 1976). These and other handling devices either operate under normal ambient conditions or use streams of air as transport means. Also known in the art are linear transfer devices, for use under vacuum conditions, which permit the movement of objects along a linear path, for example, into and out of a processing chamber through an airlock system. None of these devices is capable of serving a plurality of processing chambers belonging to the same vacuum-protected system in a circular arrangement about a central chamber.